Reading Subwindow from camera

Unity Engine
1

Hi,

I have a RenderFeature set up, and set off to go after Opaques have been rendered. i would like to read a subwindow (Rect) of the currently rendered image. i don’t think Blit(…) has that ability, and other things i’ve tried do not work.

public override void Execute(ScriptableRenderContext context, ref RenderingData renderingData)
{
// 1st attempt
Graphics.CopyTexture(BuiltinRenderTextureType.CameraTarget, myTexture);

// 2nd attempt
RenderTargetIdentifier colorBuffer = renderingData.cameraData.renderer.cameraColorTarget;
Graphics.CopyTexture(colorBuffer, myTexture);

// 3rd attempt
myTexture.ReadPixels(myRect, 0, 0);

Any help is REALLY appreciated ! :slight_smile:

2

I am surprised this has not been answered at all yet.
It depends on what you want to to with that subwindow. Do you need it’s data on the cpu (idk tell the player the value of a certain pixel in number for example) or display it again as a texture on a different object.

A camera has a viewport rect which you can modify to only render a specific portion of the screen.
And then blit that to a texture.

OR
probably the better and most simple approach. Get the full screen texture (or the URP opaque texture for example) and only transform the UVs of your display mesh / material. If you only need one specific rectangle this is the way to go and can even be done without coding at all.